This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-011046 filed Jan. 19, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a SDH signal channel pointer analyzing apparatus and a method thereof, and particularly a SDH signal channel pointer analyzing apparatus and a method thereof adopting a technology for simplifying a configuration of apparatus for carrying analysis of SDH signal channel pointer.
Conventionally, in the data transfer system of synchronized transfer mode STM-N (N is any one integer of 1, 4, 16, or 64), SDH signal whose one frame is composed of SOH (section overhead) portion of 9xc3x979xc3x97N bytes and payload portion of 9xc3x97261xc3x97N bytes is transferred as shown in FIG. 4.
An AU pointer indicating the leading head position of information inserted into the payload portion is inserted, to SOH portion of this SDH signal.
A channel pointer indicating the information leading head position or the like of a plurality of (for instance, 84) channels multiplexed and inserted in the payload portion, at the leading head position A of the payload portion indicated by this AU pointer.
In the transfer system using such SDH signal, the difference of insertion position due to phase shifting between information to be multiplexed and frame to be inserted is absorbed by adjusting the channel pointer value, when information of respective channel is to be multiplexed and inserted into the frame.
Here, this adjustment of channel pointer value is called justification.
Besides, this channel pointer value is limited in a predetermined range, and if successive pointers exceed this predetermined range, data can not be transferred correctly.
Also, it is necessary to inform of a pointer value, out of the predetermined range, or of abnormal state, by an alarm, if they succeed the predetermined number of times.
Therefore, is such SDH signal is to be processed, it is necessary to analyze the respective pointer channel increase/decrease state, the range of pointer value, or others.
Consequently, in the conventional apparatus for processing SDH signal, the channel pointer is analyzed by a channel pointer analyzing apparatus 10 as shown in FIG. 5.
First, this channel pointer analyzing apparatus 10 designate the channel to by analyzed by a channel designation means 11.
Next, the pointer of the designated channel is detected by a pointer detection means 12.
Then, increase/decrease decision of the detected pointer or range decision processing are performed by pointer processing means 13.
However, the conventional channel pointer analyzing apparatus 10 can not perform but the pointer analysis of a single channel designated by the channel designation means 11, and the pointer state of a plurality of channels inserted in the same frame of the input SDH could not be acquired at the same time.
In order to solve this problem, it can be devised to install several sets of the channel pointer analyzing apparatus 10 corresponding respectively to a plurality of channels to be analyzed.
However, this provokes another problem of increasing a configuration scale and the cost of the apparatus.
The object of the present invention is to provide a SDH signal channel pointer analyzing apparatus and method that can solve the problems mentioned above, and perform the pointer analysis of a plurality of channels inserted into the frame of SDH signal by a simple configuration at the same time.
In order to achieve the aforementioned object, according to an aspect of the present invention, there is provided a SDH signal channel pointer analyzing apparatus, comprising:
channel information detection means for sequentially detecting pointer position information of channels inserted in a frame of an input SDH signal, and channel identification information for identifying the channel, as a set of channel information;
channel pointer extraction means for extracting channel pointer value inserted in the input SDH signal based on the pointer position information contained in the channel information, each time the channel information is detected by the channel information detection means;
a reference data memory for storing channel pointer value, pointer counter data and status data representing alarm states as a set of reference data for each channel, respectively in different address area for each channel;
reference data readout means for reading out the reference data of the channel specified by channel identification information contained in the channel information from the reference data memory, each time the channel information is detected by the channel information detection means;
pointer processing means for judging states of justification and alarm, from the channel pointer value extracted from the channel pointer extraction means, and reference data read out by the reference data readout means and for generating a new reference data based on the judgment results; and
reference data update means for updating the reference data of the same channel stored in the reference data memory by the new reference data generated by the pointer processing means.
In order to achieve the aforementioned object, according to another aspect of the present invention, there is provided a SDH signal channel pointer analyzing method, comprising the steps of:
sequentially detecting pointer position information of channels inserted in a frame of an input SDH signal, and channel identification information for identifying the channel, as a set of channel information;
extracting channel pointer value inserted in the input SDH signal based on the pointer position information contained in the channel information, each time the channel information is detected;
storing channel pointer value, pointer counter data and status data representing alarm states as a set of reference data for each channel into a reference data memory, respectively in different address area for each channel;
reading out the reference data of the channel specified by channel identification information contained in the channel information from the reference data memory, each time the channel information is detected;
judging states of justification and alarm, from the extracted channel pointer value, and reference data read out from the reference data memory and, generating a new reference data based on the judgment results; and
updating the reference data of the same channel stored in the reference data memory by the new reference data.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.